Hard disk drives are common information storage devices having one or more rotatable disks that are accessed by magnetic reading and writing elements. These data transferring elements, commonly known as transducers or heads, are typically carried by and embedded in a slider body that is held in a close relative position over discrete data tracks formed on a disk to permit a read or write operation to be carried out. In order to properly position the transducer with respect to the disk surface, an air bearing surface (ABS) formed on the slider body experiences a fluid air flow that provides sufficient lift force to “fly” the slider and transducer above the rotating disk data tracks. Thus, each ABS must be precisely manufactured and processed to optimize its performance in a disk drive.
In one typical operation, a stack or chunk of multiple row bars or slider bars are manufactured using wafer processing techniques, after which lapping processes can be used to remove material at the ABS until a desired stripe height is achieved. In more particularity, a stack or chunk of row bars is processed by cutting a single bar from the stack of bars, then attaching the bar to a lapping carrier. The ABS of this mounted bar is then precisely lapped, as the ABS is a critical surface that must be polished or lapped with high accuracy in order to provide the desired performance of the drive. At any point after the first row bar is cut from the stack of bars, a subsequent row bar can be cut from the stack so that its corresponding ABS can be lapped. This process continues until the last row bar of the chunk or stack is processed.
Each row bar includes multiple adjacent sliders across its width. These sliders each include at least one electronic lapping guide (ELG) in a particularly designed location relative to the lapping surface or ABS, along with one or more corresponding ELG bond pads. The ELG can be a thin film resistor that is provided as an analog device, for example. With such an ELG, the electrical resistance is measured during processing and will increase with material removal during the lapping process. In order to monitor the ELG resistance during this process, wires are bonded to bond pads on the lapping carrier and to each row bar.
In order to monitor the ELG resistance during another exemplary lapping process, wires are bonded at one end to bond pads on a lapping carrier to which a stack of row bars are attached. The other end of each of the wires is attached to one of the multiple bond pads on the outermost row bar. When lapping the ABS, the electrical resistances of the ELGs are monitored until a resistance that corresponds to a desired stripe height of the ABS is reached. In particular, the ELG resistance can be measured, monitored, and compared to predetermined or calculated ELG resistance values to determine when a particular ELG height is reached or achieved. At this point, the lapping process can stop.
An exemplary prior art process is illustrated in FIGS. 1A-1C, which is a schematic view of three steps in processing a stack of row bars. In particular, FIG. 1A illustrates a stack 10 including multiple row bars or slider bars 12. In this embodiment, seven of such row bars 12 are shown. The stack 10 is mounted to a lapping carrier 14 that includes multiple bond pads 16 across its width. Each of multiple wires 18 are bonded at a first end to one of these bond pads 16 and bonded at a second end to one of the ELG pads 20 on the row bar 12 that is furthest from the lapping carrier 14 (i.e., the “bottom” row bar 12 in the illustration). The lapping operation can then be performed on the ABS of the row bar 12 while monitoring the electrical resistance until a desired resistance is achieved.
The wires 18 are then removed and the lowest or last row bar 12 is sliced from the stack 10, thereby exposing the ABS of the next lowest row bar 12′, as illustrated in FIG. 1B. Wires 18 are then reattached at one end to the bond pads 16 of the lapping carrier 14 and attached at the opposite wire end to one of the ELG pads 20′ of the row bar 12′. Again, the lapping operation can be performed on the ABS of the row bar 12′ while monitoring the electrical resistance until a desired resistance is achieved and the row bar 12′ is sliced from the stack 10. This process of removing and replacing wires is repeated until all of the row bars are lapped and sliced from the stack 10, which process is time consuming and requires multiple steps of attaching and removing a large number of wires. Thus, a need exists for a method of processing row bars while measuring ELG resistance that requires less processing steps and therefore is more efficient.